A team of gravitational wave researchers led by the ARC Center of Excellence for the Discovery of Gravitational Waves (OzGrav) found that when two black holes merge, the resulting formation emits several “squeaks”Which, due to their frequencies, allow us to detect the shape of the final black hole.

This finding published in the journal Communicatios Physics, is a breakthrough because it gives astronomers a unique opportunity to observe rapidly changing black holes and explore gravity in its most extreme form as well as being a major step in testing the Theory of Gravity by Albert Einstein.

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The black holes They are silent stellar entities, swallowing anything that gets too close to them not even light can escape. However, when two black holes collide and merge, they produce one of the most catastrophic events in the Universe: In a split second, a highly deformed black hole is born, releasing enormous amounts of energy as it settles into its final form. .

Although colliding black holes do not produce light, astronomers can observe the gravitational waves detected that create: waves in the structure of space and time. Scientists speculate that after a collision, the behavior of the remaining black hole is key to understanding gravity and should be encoded in the emitted gravitational waves.

This picture, by artist R. Hurt, shows the spiral structure of our galaxy, the Milky Way. The poster is extremely beautiful.
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So did Spanish, Australian and American scientists, who performed simulations of black hole collisions using supercomputers.

The shape of the final black hole

“We found that these signals are much richer and more complex than previously thought, allowing us to learn more about the enormously changing shape of the final black hole,” he says. Christopher Evans from the Georgia Institute of Technology, United States.

The teacher Juan Calderon Bustillo, OzGrav alumnus and director of the research comments “the tone and amplitude of the signal increase as the two black holes get closer and faster. After the collision, the final remaining black hole emits a signal with a constant pitch and decreasing amplitude, like the sound of a bell being rung. “

The study found, however, that something completely different happens if the collision is observed from the “equator” of the final black hole. “When we look at black holes from their equator, we find that the final black hole emits a more complex signal, with a pitch that rises and falls a few times before dying,” says Professor Calderón Bustillo. “In other words, the black hole really beeps multiple times“.